Shaft for side-by-side conveyor

ABSTRACT

A motor shaft assembly includes a first shaft, a first motor, a second shaft and a second motor. The first shaft has a first end and a second end. The first motor is attached to the first end of the first shaft and is configured to rotate the first shaft about a longitudinal axis. The first shaft and the first motor have a longitudinal bore. The second shaft has a first end and a second end, wherein a portion of the second shaft is positioned in the longitudinal bore. The second motor is attached to the first end of the second shaft and is configured to rotate the second shaft about the longitudinal axis. A conveyor assembly includes a first shaft, sprocket, motor, and conveyor, and a second shaft, sprocket, motor and conveyor. An agricultural apparatus includes a tank, a boom, conveyors and motors.

CROSS REFERENCE TO RELATED APPLICATION

This application is a continuation application of U.S. application Ser.No. 15/624,420, filed Jun. 15, 2017, now U.S. Pat. No. ______, whichapplication claims the benefit of U.S. Provisional Application No.62/356,190 filed Jun. 29, 2016, which are hereby incorporated byreference in their entirety.

BACKGROUND OF INVENTION Field of Invention

In agricultural use, a conventional pneumatic spreader for particulatematerial such as granular fertilizer includes a tank configured to bepulled across a ground surface in a travel direction.

Description of Related Art

Such a spreader typically has a pair of booms that extend transverselyoutwardly from the tank, in a lateral direction relative to the traveldirection. U.S. Pat. No. 5,052,627, which is hereby incorporated byreference, describes such a conventional spreader. As shown in FIGS. 1and 3 of the '627 patent, particulate material in tank 10 is conveyed bya pair of belts 28 into guides 60, which feed material through the pipes13 of booms 12. As shown in FIG. 1, spreader nozzles 18 and 19 allowapplication of the particulate material to a ground surface over whichthe spreader travels. A conveyer belt 29 on a right side (as viewed inFIG. 1) of tank 10 feeds into guide 60 to boom 12 on the right side offrame 11. Similarly, a conveyor belt 29 on the left side of tank 10feeds through guide 60 to a boom on the left side of the frame 11 (notshown).

U.S. Pat. No. 5,950,933, which is hereby incorporated by reference,describes a pneumatic material spreader for distributing two types ofparticulate materials simultaneously. As shown in FIG. 1 of the '933patent, tank 10 is divided into two sections by divider wall 19. (column4, line 47). Belt 46 delivers material from compartment 24 while belt 60delivers material from compartment 25. As shown in FIGS. 2 and 3 of the'933 patent, a first set of the belts 46 and 60 delivers the first andsecond materials from compartments 24 and 25, respectively, to rightboom 71. Similarly, a second set of the belts 46, 60 delivers materialsfrom compartments 24 and 25 respectively, to a left boom 70.

OVERVIEW OF THE INVENTION

In one aspect, this disclosure describes a motor shaft assemblycomprising a first shaft, a first motor, a second shaft and a secondmotor. The first shaft has a first end and a second end. The first motoris attached to the first end of the first shaft and is configured torotate the first shaft about a longitudinal axis. The first shaft andthe first motor have a longitudinal bore therethrough. The second shafthas a first end and a second end, wherein a portion of the second shaftis positioned in the longitudinal bore. The second motor is attached tothe first end of the second shaft and is configured to rotate the secondshaft about the longitudinal axis.

In another aspect, this disclosure describes a conveyor assemblycomprising a first shaft, a first sprocket, a first motor, a firstconveyor, a second shaft, a second sprocket, a second motor and a secondconveyor. The first shaft has a first end and a second end. The firstsprocket is attached to the first shaft. The first motor is attached tothe first end of the first shaft and is configured to rotate the firstshaft about a longitudinal axis, the first shaft and the first motorhaving a longitudinal bore therethrough. The first conveyor is attachedto the first sprocket. The second shaft has a first end and a secondend, wherein a portion of the second shaft is positioned in thelongitudinal bore. The second sprocket is attached to the second shaft.The second motor is attached to the first end of the second shaft and isconfigured to rotate the second shaft about the longitudinal axis. Thesecond conveyor is attached to the second sprocket.

In yet another aspect, this disclosure describes an agriculturalapparatus comprising a tank, a boom, conveyors and motors. The tank isconfigured to contain a supply of particulate material. The boom extendsoutwardly from the tank and is configured to distribute the particulatematerial, the boom comprising a plurality of boom portions along alongitudinal extent thereof. A conveyor associated with each of theplurality of boom portions. A motor is associated with each conveyor,the motor being configured to independently control a distribution rateof the particulate material on its respective conveyor and through itsrespective boom portion.

This summary is provided to introduce concepts in simplified form thatare further described below in the Detailed Description. This summary isnot intended to identify key features or essential features of thedisclosed or claimed subject matter and is not intended to describe eachdisclosed embodiment or every implementation of the disclosed or claimedsubject matter. Specifically, features disclosed herein with respect toone embodiment may be equally applicable to another. Further, thissummary is not intended to be used as an aid in determining the scope ofthe claimed subject matter. Many other novel advantages, features, andrelationships will become apparent as this description proceeds. Thefigures and the description that follow more particularly exemplifyillustrative embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

The disclosed subject matter will be further explained with reference tothe attached figures, wherein like structure or system elements arereferred to by like reference numerals throughout the several views.Moreover, analogous structures may be indexed in increments of onehundred. It is contemplated that all descriptions are applicable to likeand analogous structures throughout the several embodiments. In many ofthe drawing figures, some components are removed for purposes ofillustration. However, it is to be understood that the disclosedapparatus has features that are generally symmetrical mirror images(left to right) about line A of FIG. 1.

FIG. 1 is a rear isometric view of an exemplary embodiment of a spreaderapparatus of the present disclosure.

FIG. 2 is a perspective view of a portion of the apparatus of FIG. 1,with the boom removed, showing a distribution guide for a set of lowerconveyors.

FIG. 3 is a cross-sectional view of the apparatus of FIG. 1, taken alongthe indicated plane C, and showing distribution guides for the set ofupper conveyors.

FIG. 4 is a vertical cross-sectional view, taken along line 4-4 of FIG.2, of a portion of the exemplary spreader apparatus.

FIG. 5 is a cross-sectional view of a motor shaft assembly for the lowerconveyor assembly, as shown in FIG. 4, and additionally of a secondmirror image motor shaft assembly of the lower conveyor assembly, notshown in FIG. 4.

FIG. 6 is a front perspective view of a pair of rollers for upper andlower conveyors belts.

FIG. 7 is a cross-sectional view of a roller of FIG. 6, taken along line7-7 of FIG. 6.

FIG. 8A is a perspective view of an exemplary take-up bearing assembly.

FIG. 8B is a partially exploded view of the take-up bearing assembly ofFIG. 8A.

FIG. 9 is a top view of the take-up bearing assembly of FIGS. 8A and 8Binstalled on the spreader.

FIG. 10 is a side elevation view of a second exemplary spreaderapparatus having a single tank compartment and thus only a single levelof a conveyor belt assembly.

FIG. 11 is an exemplary hydraulic schematic for operation of the motorsin the exemplary embodiment of the apparatus shown in FIGS. 1-4.

While the above-identified figures set forth one or more embodiments ofthe disclosed subject matter, other embodiments are also contemplated,as noted in the disclosure. In all cases, this disclosure presents thedisclosed subject matter by way of representation and not limitation. Itshould be understood that numerous other modifications and embodimentscan be devised by those skilled in the art which fall within the scopeand spirit of the principles of this disclosure.

The figures may not be drawn to scale. In particular, some features maybe enlarged relative to other features for clarity. Moreover, whereterms such as above, below, over, under, top, bottom, side, right, left,etc., are used, it is to be understood that they are used only for easeof understanding the description. It is contemplated that structures maybe oriented otherwise.

DETAILED DESCRIPTION

An exemplary embodiment of agricultural spreader 20 allows fordifferential particulate application rates of material from tank 30through different portions of boom 22. As shown in FIG. 1, boom 22extends outwardly from tank 30 and is configured to distribute theparticulate material. As shown in FIGS. 1 and 3, tank 30 includes twocompartments 32 and 34 for holding supplies of different particulatematerials in a typical application. In another use, the compartments 32and 34 could hold the same type of particulate material. Lower conveyorassembly 36 delivers material from compartment 32 to boom 22, whileupper conveyor assembly 38 delivers particulate material fromcompartment 34 to boom 22. While the drawing figures show the conveyorassemblies 36, 38 only on a left side of apparatus 20, it is to beunderstood that similar, mirror-image conveyor assemblies are alsoprovided on a right side of spreader 20. As shown in FIG. 2, in anexemplary embodiment, lower conveyor assembly 36 is divided intorespective outward and inward portions 36 a, 36 b and 36 d, 36 c. Suchoutward and inward portions are separated by wall 40; one wall 40 ispositioned between outward portion 36 a and inward portion 36 b; anotherwall 40 is positioned between outward portion 36 d and inward portion 36c. Similarly, upper conveyor assembly 38 is divided into respectiveoutward and inward portions 38 a, 38 b and 38 d, 38 c. Such outward andinward portions are separated by wall 40; one wall 40 is positionedbetween outward portion 38 a and inward portion 38 b; another wall 40 ispositioned between outward portion 38 d and inward portion 38 c.

Boom 22 includes boom portions 24 a-24 d along a longitudinal extentthereof. Left boom arm 22 a includes boom portions 24 a and 24 b; rightboom arm 22 b includes boom portions 24 c and 24 d. Referring to FIGS.1-3 (as partially illustrated), for distribution of particulate materialfrom compartment 32 of tank 30, lower conveyor belt 56 a on lowerconveyor side 36 a is associated with boom portion 24 a; lower conveyorbelt 56 b on lower conveyor side 36 b is associated with boom portion 24b; lower conveyor belt 56 c on lower conveyor side 36 c is associatedwith boom portion 24 c; and lower conveyor belt 56 d on lower conveyorside 36 d is associated with boom portion 24 d. For distribution ofparticulate material from compartment 34 of tank 30, upper conveyor belt58 a on upper conveyor side 38 a is associated with boom portion 24 a;upper conveyor belt 58 b on upper conveyor side 38 b is associated withboom portion 24 b; upper conveyor belt 58 c on upper conveyor side 38 cis associated with boom portion 24 c; and upper conveyor belt 58 d onupper conveyor side 38 d is associated with boom portion 24 d.

In an exemplary embodiment, the particulate application rates can bedifferent for each of the materials from compartments 32 and 34 betweendifferent sections 24 a through 24 d, for example, along thelongitudinal extent of boom 22. A separate motor 66 a-66 d and 68 a-68 dis associated with each of the lower and upper conveyor belts 56 a-56 dand 58 a-58 d, each motor 66 a-66 d and 68 a-68 d being configured toindependently control a distribution rate of the particulate material onits respective conveyor belts 56 a-56 d and 58 a-58 d and through itsrespective boom portion 24 a-24 d.

For example, as shown in FIG. 1, if spreader 20 travels across a groundsurface so that it turns in leftward turn direction 28, the leftmostboom portion 24 a will travel at the slowest speed relative to the otherboom portions, and the rightmost boom portion 24 d will travel at thehighest rate of speed while traversing the turn 28. Accordingly, inorder to uniformly spread particulate material on a ground surface belowthe entire boom structure 22, particulate material should be depositedto the ground surface at a faster application rate in boom portion 24 das compared to that in boom portion 24 a. Moreover, particulateapplication rates through boom portions 24 b and 24 c should be proratedbetween the speed extremes at boom portions 24 a and 24 d to ensure auniform application of particulate material to the ground surface acrossthe entire width of spreader 20.

Material moved on a conveyor side 36 a falls by gravity into lower guide42 a. Similarly, material moved by lower conveyor side 36 b falls bygravity into lower guide 42 b. Each of lower guides 42 a, 42 b includesa plurality of compartments 44, each of the compartments 44 fluidlyconnected to one of outlets 46. Each of the outlets 46 is in turnconnected to a boom pipe 48, which has a spreader nozzle 50 at itsterminus.

Referring to FIGS. 2 and 3, material moved by upper conveyor side 38 ais fed by gravity to upper guide 52 a (not shown, as it is positioned tothe left of the cross-sectional plane C); material fed by upper conveyorside 38 b falls by gravity into upper guide 52 b. Material conveyed byupper conveyor side 38 c falls by gravity into upper guide 52 c, andmaterial conveyed by upper conveyor side 38 d falls by gravity intoupper guide 52 d. As with lower guide 42, each of the compartments 54 ofupper guide 52 are in fluid communication with an outlet 46, which inturn allows particulate material to travel through boom pipes 48 tospreader novels 50. While such boom pipes 48 and spreader nozzles 50 arenot shown on the right boom arm 22 b of FIG. 1, it is to be understoodthat they are provided similarly as shown on the left boom arm 22 a.

In an exemplary embodiment, material flow on each of the lower and upperconveyor sides 36 a, 36 b, 36 c, 36 d, 38 a, 38 b, 38 c and 38 d isindependently controlled by a separate motor. In an exemplaryembodiment, material moved by conveyor sides 36 a and 38 a through lowerguide 42 a and upper guide 52 a are applied to the ground surfacebeneath spreader 20 by nozzles 50 on boom portion 24 a. Similarly,material moved on lower conveyor side 36 b and upper conveyor side 38 bthrough lower guide 42 b and upper guide 52 b, respectively, are appliedto the ground surface through nozzles 50 on boom portion 24 b. In a likemanner, material moved on lower conveyor side 36 c and upper conveyorside 38 c through lower guide 42 c and upper guide 52 c, respectively,are applied to a ground surface through nozzles 50 on boom portion 24 c.Moreover, material moved on lower conveyor side 36 d and upper conveyorside 38 d through lower guide 42 d and upper guide 52 d, respectively,are applied to the ground surface through nozzles 50 positioned on boomportion 24 d. Because a rate of particulate material flow through eachof the upper and lower conveyor sides 36 a-d and 38 a-d is independentlycontrolled by a corresponding number of individual conveyor belt motors,a rate of delivery of material through each of the boom portions 24 a,24 b, 24 c and 24 d can be independently controlled for each of theparticulate materials in compartments 32 and 34 of tank 30.

Thus, in an exemplary use where spreader 20 navigates a left-hand turn28, the flow of material through boom portion 24 a can be controlled tobe applied at a slowest relative rate, the flow of material through boomportion 24 b controlled to be applied at a higher speed than throughboom portion 24 a, a rate of particulate application through boomportion 24 c can be controlled to be administered at a still higher rateof speed than through boom portion 24 b; and a relative application rateof materials through boom portion 24 d can be controlled to be at thehighest speed relative to the other boom portions 24 a-24 c.

While a particular situation is described herein, it is to be understoodthat the differential particulate application rates of the two materialsfrom compartments 32 and 34 through boom portions 24 a-24 d can bevaried to take into account other movements of apparatus 20 over aground surface. Such differential speed control of the motors 66 a-66 dand 68 a-68 d (further described below) of lower conveyor assembly 36and upper conveyor assembly 38, respectively, can be automated throughthe use of computer controllers and global positioning system (GPS)devices. The differential application speed control through differentportions 24 a-24 d of booms 22 can also receive inputs from steeringapparatuses and/or other input devices that sense or react to thedirection and rate of travel of spreader 20 over a ground surface.Moreover, computer and GPS devices can be programmed to take intoaccount the location of previous application passes so that certainmotors can be turned off or their speed of application decreased, tostop or slow application through a particular one or selected boomportions 24 a-d, thus preventing over-application when spreader 20travels over a particular parcel of the ground surface more than once.Additionally, spreader 20 may also be programmed or otherwise configuredfor map based particulate application; for example, each boom sectioncan apply particulate material to the ground surface at a different ratebased on a prescription map of the field.

While a particular configuration of spreader 20 is illustrated anddescribed, having four boom sections 24 a-d and four correspondingsections of each of lower conveyor assembly 36 and upper conveyorassembly 38, it is to be understood that the disclosed concepts can bereadily expanded to provide for differential application rates throughmore or fewer boom sections or portions. Moreover, while a particularcorrelation of conveyor sections to boom portions is described, it isunderstood that the guides 42, 52, pipes 48, nozzles 50 and boomportions can be set up differently to provide for other correlationsbetween the conveyor sections and the locations of material applicationto a ground surface under spreader 20.

While not illustrated, it is to be understood that apparatus 20 istypically provided with ground engaging elements such as wheels or atrack that allow spreader 20 to travel across a ground surface in adirection generally perpendicular to the longitudinal orientation ofboom 22. In one typical use, spreader 20 is pulled behind anotheragricultural implement, such as a tractor. In other configurations,spreader 20 is self-propelled on its own chassis.

As shown in FIG. 3, in an exemplary embodiment, each of lower and upperconveyor assemblies 36, 38 includes endless conveyor belt 56, 58 that isconfigured to move (in a clockwise direction as viewed in FIG. 3) aroundsprocket 57, roller 60, drive sprocket 62 and tension rod 64. As shownin FIGS. 2 and 4, in an exemplary embodiment, of spreader 20, lowermotor 66 a controls the speed of particulate material moved on lowerconveyor side 36 a; lower motor 66 b controls the speed of materialconveyed on lower conveyor 36 b; upper motor 68 a controls the speed ofmaterial moving an upper conveyor side 36 a; and upper motor 68 bcontrols the speed of material moving on upper conveyor side 38 b. Asshown in FIG. 2, a portion of an outward conveyor 56 a, 58 a is alignedside-by-side with a portion of a corresponding inward conveyor 56 b, 58b in a plane substantially parallel to the longitudinal axis 88. Whilenot specifically illustrated in FIGS. 1-4, it is to be understood thatmirror image motor shaft assemblies 70 are also provided for the rightside conveyor portions 36 c, 36 d, 38 c and 38 d.

FIG. 5 is a cross-sectional view of two longitudinally aligned motorshaft assemblies 70, as would be used for either the lower conveyorassembly 36 or the upper conveyor assembly 38. While the components inFIG. 5 are numbered for the lower conveyor assembly 36, it is beunderstood that the motor shaft assemblies 70 can also be used in upperconveyor assembly 38. FIGS. 2 and 4 show two motor shaft assemblies 70,one each on the left side of lower conveyor assembly 36 and on the leftside of upper conveyor assembly 38. It is to be understood that motorshaft assemblies 70 for the right side of lower conveyor assembly 36 andof upper conveyor assembly 38 are installed as mirror image structures,compared those illustrated in FIGS. 2 and 4.

As shown in FIG. 5, in an exemplary embodiment, first motor shaft 74 ahas a first end 128 a and a second end 130 a. First motor 66 a isattached to first end 128 a of first motor shaft 74 a. First motor 66 ais configured to rotate first motor shaft 74 a about longitudinal axis88. First motor shaft 74 a and first motor 66 a have longitudinal bore76 therethrough. Second motor shaft 74 b has a first end 128 b and asecond end 130 b. A portion of second motor shaft 74 b is positioned inlongitudinal bore 76. Second motor 66 b is attached to first end 128 bof second motor shaft 74 b. Second motor 66 b is configured to rotatesecond motor shaft 74 b about longitudinal axis 88. On a right side ofFIG. 5, third motor shaft 74 d has a first end 128 d and a second end130 d. Third motor 66 d is attached to first end 128 d of third motorshaft 74 d. Third motor 66 d is configured to rotate third motor shaft74 d about longitudinal axis 88. Third motor shaft 74 d and third motor66 d have longitudinal bore 76 therethrough. Fourth motor shaft 74 c hasa first end 128 c and a second end 130 c. A portion of fourth motorshaft 74 c is positioned in longitudinal bore 76. Fourth motor 66 c isattached to first end 128 c of fourth motor shaft 74 c. Fourth motor 66c is configured to rotate fourth motor shaft 74 c about longitudinalaxis 88.

Motor 66 a is attached to housing side wall 72 of spreader 20 (shown inFIGS. 2 and 4). Motor shaft 74 a of motor 66 a carries drive sprockets62 a, which couple with endless drive conveyor belt 56 a in a knownmanner. Motor shaft 74 b of motor 66 b extends through bore 76 in motor66 a and motor shaft 74 a. Second end 130 b of motor shaft 74 b isattached to bearing 78, positioned on bracket 80 connected to housingwall 132, shown in FIGS. 2 and 4. Motor 66 d is attached to housing sidewall 72 of spreader 20. Motor shaft 74 d of motor 66 d carries drivesprockets 62 d, which couple with endless drive conveyor belt 56 d in aknown manner. Motor shaft 74 c of motor 66 c extends through bore 76 inmotor 66 d and motor shaft 74 d. Second end 130 c of motor shaft 74 c isattached to bearing 78, positioned on bracket 80 connected to housingwall 132, shown in FIGS. 2 and 4. The use of only a single bearing 78for each motor shaft assembly 70, reduces lubrication requirements andwear points.

In an exemplary embodiment, enough clearance is provided around secondmotor shaft 74 b through bore 76 that no physical contact is madebetween second motor shaft 74 b and first motor 66 a or first motorshaft 74 a. Such an arrangement eliminates a need for bearings betweenmotor shaft 74 b and motor 66 a or its motor shaft 74 a. In effect,motor shaft 74 a is cantilevered from motor 66 a and is not supported onmotor shaft 74 b. Motor shaft 74 b is turned by motor 66 b and carriesdrive sprockets 62 b, on which endless belt 56 b moves. Moreover, enoughclearance is provided around third motor shaft 74 c through bore 76 thatno physical contact is made between third motor shaft 74 c and fourthmotor 66 d or fourth motor shaft 74 d. Such an arrangement eliminates aneed for bearings between motor shaft 74 c and motor 66 d or its motorshaft 74 d. In effect, motor shaft 74 d is cantilevered from motor 66 dand is not supported on motor shaft 74 c. Motor shaft 74 c is turned bymotor 66 c and carries drive sprockets 62 c, on which endless belt 56 cmoves. An exemplary suitable motor is available commercially fromPoclain Hydraulics under compact motor model MK04. However, it iscontemplated that other motors for rotationally driving a shaft are alsosuitable, including motors driven electrically, pneumatically, and byother methods.

As shown in FIG. 2, outward and inward conveyor belts 56 a and 56 b areseparate, and outward and inward conveyor belts 58 a and 58 b areseparate, and are thereby able to carry particulate material atdifferent rates of speed. While not shown but described in this writtendescription, inward and outward conveyor belts 56 c and 56 d are alsoseparate, and inward and outward conveyor belts 58 c and 58 d areseparate, and are thereby able to carry particulate material atdifferent rates of speed. In an exemplary embodiment, portions ofconveyor belts 56 a, 56 b, 56 c, 56 d are aligned side-by-side in alower plane parallel to longitudinal axis 88 of lower conveyor assembly36; and portions of conveyor belts 58 a, 58 b, 58 c, 58 d are alignedside-by-side in an upper plane parallel to longitudinal axis 88 of upperconveyor assembly 38.

FIG. 11 shows a schematic diagram of an exemplary hydraulic circuit 82for the operation of motors 66 a-66 d for control of the speed ofmaterial application through lower conveyor sides 36 a-36 d,respectively. Hydraulic circuit 82 also shows the use of motors 68 a-68d for control of material application motion rates through upperconveyor sides 38 a-38 d, respectively. In an exemplary embodiment, thehydraulic system used in spreader 20 and depicted in diagram 82 is ahybrid of series and parallel connections for hydraulic fluid from pump84. Referring to FIG. 3, in an example, if particulate material is to beconveyed only from compartment 32 of tank 30 and not compartment 34,then upper motors 38 a-38 d will be turned off and only lower motors 66a-66 d will receive hydraulic fluid from pump 84. Moreover, in anexample where, with reference to FIG. 1, boom portion 24 a is to passover an area of the ground that has already received an application ofparticulate matter, motor 66 a can be turned off so that fluid from pump84 bypasses motor 66 a, thereby operating motors 66 b-66 d to allow forapplication of particulate material from conveyor sides 36 b, 36 c and36 d through nozzles 50 of boom portions 24 b, 24 c and 24 d. In anexemplary circuit 82 depicted in FIG. 11, a relief valve 86 is providedfor excess hydraulic fluid that is not used by the connected motors 66,68. In an exemplary embodiment, flow can be modulated through each ofthe motors 66, 68 to provide for an infinitely variable speed ofrotation of connected motor shafts 74 between off and maximum speedextremes. Thus, precise control of the rate of application ofparticulate material from each compartment 32, 34 can be controlledindependently at each of boom portions 24 a-24 d.

As shown in FIG. 5, motor shaft 74 a and motor shaft 74 b are co-axial,in that they rotate about a common longitudinal axis 88. Moreover, motorshaft 74 c and motor shaft 74 d are co-axial. However, the shafts areindependently controlled by their respective motors 66 a-66 d andthereby independently drive their respectively connected conveyor beltsides 56 a-56 d. This configuration allows for independent driving ofthe adjacent conveyor belt sides 56 a, 56 b and 56 c, 56 d in a smallamount of space, and with few required bearings. Independent speedcontrol of the motor shafts 74 a-74 d and their corresponding conveyorsides 56 a-56 d permit variable rate application of the particulatematerial conveyed thereon, as well as sectional control of the variablerate application, with application rates for the separate materials ofcompartments 32 and 34 at each boom portion 24 a-24 d beingindependently controllable.

The series and bypass valve arrangements of circuit 82 (FIG. 11) reduceflow requirements for pump 84 while still allowing for independentcontrol of each motor 66 a-d and 68 a-d. At each valve corresponding toeach of the individual motors, whatever hydraulic fluid flow is notdirected through that motor will flow to the next motor. In this way,all of the hydraulic fluid flow is available to each motor in eachseries portion of the circuit, thereby allowing for independent controlof each of the individual motors. The illustrated circuit 82 has twoparallel branches; one for lower motors 66 a-d and another for uppermotor 68 a-d. With this arrangement, each of the first motors 66 a, 68 ain the parallel branches encounters a reduced pressure load, as comparedto a circuit in which all of the motors are arranged in series with eachother.

As shown in FIGS. 2, 3 and 6, conveyor belts 56, 58 travel aroundrollers 60, allowing particulate material on a top surface of conveyorbelt 56, 58 to fall into compartments 44, 54 of guides 42, 52. FIG. 6shows front perspective views of the upper and lower rollers 60, removedfrom spreader 20. FIG. 7 is a vertical cross-sectional view of one ofthe rollers 60 through section line 7-7 of FIG. 6. As shown in FIG. 7,roller 60 includes shaft 104 having first end 134, second end 136, andlongitudinal axis of rotation 102. Inward barrel 96 surrounds a firstportion of shaft 104 and is fixed to shaft 104 to rotate therewith.Outward barrel 94 surrounds a second portion of shaft 104 and isconfigured to rotate about axis 102 independent of a rotation of shaft104. Outward barrel 94 is spaced from inward barrel 96 along axis 102.Spacer 98, in block or annular form, is positioned to at least partiallysurround shaft 102 and is positioned between inward barrel 96 andoutward barrel 94.

External bearings 90 are provided at each of mounting brackets 92. In anexemplary embodiment, each external bearing 90 is positioned within therespective mounting bracket 92 and accepts an end 134, 136 of shaft 104.Roller 60 includes outward barrel 94, around which outward conveyor belt56 a, 56 d, 58 a or 58 d partially wraps and inward barrel 96, aroundwhich inward conveyor belt 56 b, 56 c, 58 b or 58 c partially wraps.Spacer 98 separates the outward barrel 94 and the inward barrel 96 andis formed in an exemplary embodiment of a durable polymer material.Annular bearings 100, such as formed from composite materials, areprovided to allow outward barrel 94 and inward barrel 96 to rotateindependently about a common longitudinal access 102 of shaft 104. Anannular bearing 100 is positioned at least partially between the shaft104 and the spacer 98. In an exemplary embodiment, spacer 98 also servesas a seal to keep fertilizer, debris, and other material away frombearing 100 b. Additional seals (e.g., o-rings or lip seals) can also beintegrated into spacer 98 to improve its performance. Moreover, annularbearing 100 is positioned at least partially between the shaft 104 andthe outward barrel 94.

Outward barrel 94 and inward 96 are configured to rotate independentlyfrom each other. Each of outward barrel 94 and inward 96 rotate at aspeed determined by the rate of movement of its corresponding conveyorbelt 56 a-d, 58 a-d, respectively. In an exemplary embodiment, commonshaft 104 rotates on external bearings 90. In an exemplary embodiment,inward barrel 96 is welded or otherwise fixedly attached directly toshaft 104, to rotate therewith on the main external bearings 90. In anexemplary embodiment, inward barrel 96 is substantially hollow to reducea total weight of roller 60.

Outward barrel 94 is free to rotate on shaft 104 at a different speedthan inward barrel 96 by means of annular bearings 100. In an exemplaryembodiment, annular bearings 100 are press fit into machined recesses106 on an internal surface of outward barrel 94. In an exemplaryembodiment, spacer 98 is formed of a wear resistant polymer, possibly anultrahigh molecular weight polymer, and is located between outwardbarrel 94 and inward barrel 96. Spacer 98 provides a seal and a wearresistant element between the barrels 94, 96. In the illustratedembodiment, outward annular bearing 100 a is positioned proximate end134 and extends to mounting bracket 92. This prevents particulatematerial from entering that end of bearing 100 a and also constrainsmotion of bearing 100 a in a leftward direction as viewed in FIG. 7.Moreover, spacer 98 prevents rightward or inward motion of outwardbarrel 94 along shaft 104. In the illustrated structure, becausebearings 100 a and 100 b will wear at essentially identical rates, noangular misalignment will result from a change in the thickness of theannular bearings 100 a,b due to wear. In an exemplary embodiment,annular bearings 100 are sealed, maintenance free composite bearingsthat do not require lubrication. In another embodiment, ball bearings orother bearings could be used instead of composite bearings; however,such ball bearings would require regular lubrication. While an exemplaryconfiguration of roller 60 is illustrated and described, it iscontemplated that roller 60 may be constructed differently than shown.For example, the outward barrel may be fixed to shaft 104 and the inwardbarrel may rotate independently of shaft 104.

As shown in FIGS. 1, 3 and 8A-9, take-up bearing assembly 108 isprovided near a forward end of each conveyor belt 56, 58 and containssprockets 57, around which conveyor belts 56, 58 travel. While FIG. 9 islabeled for lower conveyor assembly 36, it is to be understood that thedescriptions also apply to upper conveyor assembly 38. Outward conveyorbelt 56 a partially wraps and travels around sprockets 57 a, and inwardconveyor belt 56 b partially wraps and travels around sprockets 57 b.Each of sprockets 57 is attached to bearing shaft 110 to rotatetherewith. First bearing shaft 110 a has first end 138 a, second end 140a, and first longitudinal axis of rotation 142 a. Sprockets 57 a areattached to first bearing shaft 110 a proximate first end 138 a of firstbearing shaft 110 a. Sprockets 57 a rotate with first bearing shaft 110a about first longitudinal axis of rotation 142 a. Second bearing shaft110 b is spaced from first bearing shaft 110 a by a distance D alongdirections 112. Second bearing shaft 110 b has first end 138 b spacedfrom first end 138 a of first bearing shaft 110 a by distance D and asecond end 140 b spaced from second end 140 a of first bearing shaft 110a by distance D. Second longitudinal axis of rotation 142 b of secondbearing shaft 110 b is substantially parallel to first longitudinal axisof rotation 142 a of first bearing shaft 110 a. Sprockets 57 b areattached to second bearing shaft 110 b proximate second end 140 b ofsecond bearing shaft 110 b. Sprockets 57 b rotate with second shaft 110b about second longitudinal axis of rotation 142 b.

As conveyor belts 56 a, 56 b change in length due to wear, shafts 110 aand 110 b of take-up bearing assembly 108 can be moved relative to otherstructures of spreader 20 in directions 112 to take up slack in therespective belt or belts 56 a, 56 b. Although shafts 110 a and 110 b canbe moved independently, such movement also adjusts or changes distance Din most cases. However, it is to be understood that positional changesof both shafts 110 a and 110 b of the same amount and in the samedirection may ultimately result in maintaining the same distance Dbetween the shafts 110 a, 110 b.

Rods 116 pass through apertures 144 in plates 118. Adjustment in anexemplary embodiment is accomplished by threading nuts 114 along rods116 against mounting plates 118. Providing two separate bearing shafts110 a, 110 b allows for independent adjustment of the tension of the twoconveyor belt sides 56 a, 56 b. In the illustrated embodiment, bearingshaft 110 a rotates on bearings 120 a mounted on rails 122 a in plates124 a. Similarly, bearing shaft 110 b rotates on bearings 120 b carriedon rails 122 b, which are in turn mounted on plates 124 b. Grooves 126in top and bottom surfaces (grooves in bottom surfaces not shown) ofbearing housings 122 allow the bearing housings 122 to move within rails124 only in directions 112.

FIG. 9 is a top view of a portion of an inside of spreader 20, showingthe locations on which conveyor belts 56 a, 56 b would be positioned;however, the conveyor belts themselves are not shown to allow a view ofthe components of take-up bearing assembly 108. In the illustratedembodiments, plates 124 of take-up assembly 108 are mounted on sidewalls72 of spreader 20. When conveyor belts 56 a, 56 b are wrapped at leastpartially around their respective first and second sprockets 57 a, 57 b,a portion of the outward conveyor belt 56 a and a portion of the inwardconveyor belt 56 b are aligned alongside each other in a planesubstantially parallel to the axes of rotation 142 a, 142 b.

FIG. 10 is a side elevation view of a second exemplary spreader 220having a tank 230 with a single compartment therein, rather than thedual compartments 32, 34 of spreader 20. Accordingly, only a lowerconveyor assembly 236 is used in each of the left and right sides ofspreader 220. In other aspects, spreader 220 is similar to spreader 20,allowing independent control of application rates of the particulatematerial in tank 230 through four boom portions, and analogous parts aresimilarly labeled.

Although the subject of this disclosure has been described withreference to several embodiments, workers skilled in the art willrecognize that changes may be made in form and detail without departingfrom the scope of the disclosure. In addition, any feature disclosedwith respect to one embodiment may be incorporated in anotherembodiment, and vice-versa.

What is claimed is:
 1. A motor shaft assembly comprising: a first shaft having a first end and a second end; a first motor attached to the first end of the first shaft and configured to rotate the first shaft about a longitudinal axis, the first shaft and the first motor having a longitudinal bore therethrough; a second shaft having a first end and a second end, wherein a portion of the second shaft is positioned in the longitudinal bore; and a second motor attached to the first end of the second shaft and configured to rotate the second shaft about the longitudinal axis.
 2. The assembly of claim 1 further comprising a bearing connected to the second end of the second shaft.
 3. The assembly of claim 1 wherein there is no physical contact between the second shaft and the first shaft.
 4. The assembly of claim 1 wherein there is no physical contact between the second shaft and the first motor.
 5. The assembly of claim 1 further comprising a sprocket attached to the first shaft.
 6. The assembly of claim 1 further comprising a sprocket attached to the second shaft.
 7. A conveyor assembly comprising: a first shaft having a first end and a second end; a first sprocket attached to the first shaft; a first motor attached to the first end of the first shaft and configured to rotate the first shaft about a longitudinal axis, the first shaft and the first motor having a longitudinal bore therethrough; a first conveyor attached to the first sprocket; a second shaft having a first end and a second end, wherein a portion of the second shaft is positioned in the longitudinal bore; a second sprocket attached to the second shaft; a second motor attached to the first end of the second shaft and configured to rotate the second shaft about the longitudinal axis; and a second conveyor attached to the second sprocket.
 8. The assembly of claim 7 wherein a portion of the first conveyor is aligned side-by-side with a portion of the second conveyor in a plane substantially parallel to the longitudinal axis.
 9. The assembly of claim 7 wherein at least one of the first conveyor and second conveyor is configured as an endless belt.
 10. The assembly of claim 7 further comprising a first housing wall to which the first motor is attached.
 11. The assembly of claim 10 further comprising: a second housing wall; and a bearing connected to the second end of the second shaft and to the second housing wall.
 12. The assembly of claim 7 wherein there is no physical contact between the second shaft and the first shaft.
 13. The assembly of claim 7 wherein there is no physical contact between the second shaft and the first motor.
 14. The assembly of claim 7 further comprising: a third shaft having a first end and a second end; a third sprocket attached to the third shaft; a third motor attached to the first end of the third shaft and configured to rotate the third shaft about the longitudinal axis, the third shaft and the third motor having a longitudinal bore therethrough; a third conveyor attached to the third sprocket; a fourth shaft having a first end and a second end, wherein a portion of the fourth shaft is positioned in the longitudinal bore; a fourth sprocket attached to the fourth shaft; a fourth motor attached to the first end of the second shaft and configured to rotate the fourth shaft about the longitudinal axis; and a fourth conveyor attached to the fourth sprocket. 